THE JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT Formerly The Journal of Resource Management and Technology (Volumes 12-22) Formerly NCRR Bulletin (Volumes 1-11) August 2009 Volume 35 Number 3 UNIVERSITY OF IBADAN LIBRARY THE JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT ISSN: 1088-1697 Indexed/Abstracted by: Chemical Abstracts; Engineering Abstracts; Environmental Abstracts; Environmental Periodicals Bibliography; Pollution Abstracts, All- Russian Institute of Scientific and Technical Information (VINITI, REFERATIVNYI ZHURNAL ) EDITOR AND FOUNDER: EDITOR: ASSOCIATE EDITOR: Iraj Zandi Ronald L. Mersky Wen K. Shieh University of Pennsylvania Widener University University of Pennsylvania U.S.A. U.S.A. U.S.A. REGIONAL EDITORS North America David Smith Africa Tom Falcone The Regional Municipality of Niagara Chukwu Onu Indiana University of Pennsylvania Public Works Department Department of Civil Engineering U.S.A. Waste Management Services Division Southern University 2201 St. David’s Road, P.O. Box 1042 Southern Branch Post Office A.J. Griffins Thorold, Ont., L2V 4T7, Canada Baton Rouge, LA 70813, U.S.A. Cardiff University Email: Email: onu@engr.subr.edu U.K. david.smith@regional.niagara.on.ca South and East Asia Patrick Hettiaratchi Shoou-Yuh Chang Kasturi Gadgil University of Calgary Department of Civil Engineering Centre for Energy Studies Canada North Carolina A&T State University Indian Institute of Technology (IIT) Greensboro, NC 27411, U.S.A. New Delhi - 110016, India Mervat El-Hoz Email: chang@ncat.edu Email: kgadgil2k@yahoo.com University of Balamand Lebanon Middle East South and Central America Emanuel Azmon Cristina Braga Gennaro J. Maffia Prof. Emeritus Universidade Federal do Paraná Widener University Ben-Gurion University Setor de Tecnologia U.S.A. P.O. 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Northampton, NN2 7AL, U.K. Sarvesh Chandra Email: paul.phillips@northampton.ac.uk Ming-Yen Wey Indian Institute of Technology Kanpur National Chung Hsing University India Adam Read Republic of China Knowledge Leader – Ni-Bin Chang Waste & Resources Management Keith P Williams University of Central Florida AEA Cardiff University U.S.A The Gemini Building U.K. Harwell IBC Jess Everett Didcot Oxon OX11 0QR, U.K. Anita Závodská Rowan University Email: Adam.Read@uk.aeat.com Barry University U.S.A U.S.A. The Journal of Solid Waste Technology and Management, is published by Widener University School of Engineering. The responsibility for contents rests upon the authors and not upon the University. This journal is available by subscription and may be purchased at the rate of US$130 per volume (4 issues) for individuals and US$305 for libraries, businesses and organizations. Editorial and subscription address is: Department of Civil Engineering, Widener University, One University Place, Chester, PA 19013-5792, U.S.A.; Telephone (610) 499-4042; Fax (610) 499-4461. Email: solid.waste@widener.edu. Web site: www.widener.edu/solid.waste. Copy- right © 2009 by Widener University. Printed in U.S.A. UNIVERSITY OF IBADAN LIBRARY EFFECTS OF PHOSPHATE CHEMICALS TREATMENTS ON AUTO BATTERY WASTE CONTAMINATED SOIL IN NIGERIA M.B. Ogundiran* and O. Osibanjo Analytical/Environmental Unit Department of Chemistry University of Ibadan NIGERIA ABSTRACT Auto battery waste contaminated site poses potential threats to the environment and biological life through lead toxicity, thus making remediation imperative. The possibility of using phos- phate chemicals to reclaim a grossly lead-contaminated site was explored. The study site was an abandoned lead-acid battery waste dumpsite in Nigeria. Phosphate chemicals were applied at 5 and 10% phosphorus levels to the contaminated soil collected from the site in incubation experiments. The air-dried sub-samples of the incubated soils were analyzed for pH, P, bioavailable Pb and TCLP- extractable Pb. Results showed that 99.5% of the applied phospho- rus was removed by the end of the first week of incubation. Incubation time showed less effect on Pb immobilization. A 10% phosphorus application resulted in reductions of water soluble Pb between 77.8% and 86.4% thus eliminating to a reasonable extent, the hazard to living things and the environment. TCLP extractable Pb was reduced from 50.2 mg/L in untreated soil to be- low the acceptable value of 5.0 mg/L. An application of 10% CHP produced overall effective- ness in the reduction of bioavailable Pb, TCLP-extractable soil Pb. This treatment also had little effect on soil acidification and resulted in the least residual P. Results therefore indicated that phosphorus can be used as potential chemical remediation for cleanup of battery waste con- taminated soils. Keywords: Lead; contaminated soil; battery waste; remediation; phosphate chemicals; speci- ation INTRODUCTION the general environment (Balkrishena et al, 1999; Andy and Roberts, 2002; Boularbah et al., 2006; Everhart et al., 2006; Contamination by heavy metals is a global concern due Sanghoon, 2006; Li et al., 2005; Peplow and Edmonds, 2005; to its threats to all living things and the environment. There Chopin et al., 2003). Lead contamination particularly is of are documented reports identifying waste from industrial ac- great concern owing to its outcome on human health in terms tivities as the major route by which heavy metals reach the of neurological, metabolic and behavioral changes produced soil at the levels that are precarious to living organisms and in children (Kaul et al., 1999; ATSDR, 2005). ________________________________________________ * Corresponding author: Email: mbogundiran@yahoo.com EFFECTS OF PHOSPHATE CHEMICALS TREATMENTS ON AUTO BATTERY WASTE CONTAMINATED SOIL IN NIGERIA 181 UNIVERSITY OF IBADAN LIBRARY The effectiveness of phosphate chemicals in immobiliz- Soil properties ing bioavailable Pb in Pb contaminated soils has been well documented. Many bench scale batch, continuous flow col- Total environmentally available Pb was assessed in the umn, incubation, pot and field experiments have been con- experimental soil using 2 M HNO3. Soil pH was measured in ducted by researchers on lead-contaminated soils to deter- a 1:1 ratio of soil to water (w/v) using a glass electrode pH mine the rate and extent of lead immobilization with phos- meter. Available phosphorus was extracted with Olsen’s re- phorus amendments (Ma et al. 1995; Ma and Traina, 1999; agent (0.5 M NaHCO3 adjusted to pH 8.2, 1:20 soil/solution Berti and Cunningham, 1997; Ownby et al., 2005; Laperche ratio) and determined colorimetrically by molybdenum blue et al., 1996; McGowen et al., 2001; Brown et al., 2004; Chen ascorbic acid method (Stewart, 1989). The hazardous status et al., 2003; Yang and Mosby, 2006). Pyromorphites have of the soil was tested using Toxicity Characteristic Leaching been reported to be stable over a wide range of environmental procedure (TCLP, SW-846 Method 1311) (USEPA 1992). conditions and are biologically inert. In addition, they do not dissolve in the human digestion system even when ingested, Addition of phosphate chemicals but rather pass through unabsorbed without being deleterious (Ma et al., 1995; Zhang and Ryan, 1998). In preliminary optimization experiments, the different P The site for the present study was polluted with auto bat- sources at application rates of 0 %, 5 %, 10 %, 15 % and 20 tery waste by a defunct automobile battery manufacturing % were applied to the experimental soil to determine the ex- company located at Lalupon, Ibadan, Nigeria. The company tent of reduction of bioavailable Pb. Through this experiment, dumped slag obtained from the lead smelting operations it was discovered that there was no significant difference be- spanning from 1996 to 1998. A huge pile of waste by the tween the effects produced by 10 % and 15 % phosphorus company was left in the open and untreated. The preliminary application. This formed the basis for choosing the following study showed that lead levels ranged from 120-124 000 and phosphorus amendment treatments in the form of DAP, CHP 25.4-4300 mg Pb/kg soil in the waste and the surrounding and DAP + CHP, each at application rates of 0 %, 5 %, and soils respectively, indicating levels higher than the clean-up 10 %. An application rate of 0 % represented the control, level (400 mg/Kg) of Pb in soil. Based on the pilot study, the which was contaminated soil without the addition of an site constituted a potential hazard to the environment and amendment. biologic life, hence the need for decontamination of the site. Seven treatments with 100 % duplicates were examined: The objective of the study was to evaluate the remediation 1. 0 % ( 1.0 kg soil + 0.0 g amendment); effects of phosphate chemical treatments on the auto battery 2. 5 % P as DAP (1.0 kg soil + 28.1 g DAP); waste contaminated soil. 3. 10 % P as DAP (1.0 kg soil + 56.3 g DAP); 4. 5 % P as CHP (1.0 kg soil + 29.9 g CHP); Materials and methods 5. 10 % P as CHP (1.0 kg soil +59.7 g CHP); 6. 3.75 % P as DAP + 1.25 % P as CHP (1.0 kg soil + 21.1 Site description g DAP + 7.5 g CHP); 7. 5 % P as DAP + 5 % P as CHP (1.0 kg soil + 28.1 g A lead-acid battery manufacturing company located at DAP + 29.9 g CHP). Lagelu Local Government area of Ibadan, Nigeria dumped solid waste slag on a hectare of land in a disused quarry situ- Procedure ated in Lalupon on the outskirts of Ibadan. The company had since gone into liquidation. Selected waste and soil samples A large quantity mixture of soil and waste sample was tested for Toxicity characteristic Leaching procedure (TCLP) collected from the area of highest contamination as revealed had mean values of leachable lead of 171 and 63.9 mg Pb/L by the pilot study. This mixture was air dried, homogenized respectively. These values categorized the waste and the sur- by grinding and then sieved through a < 2 mm pore sieve. An rounding soils as hazardous and requiring remediation. analysis of the sample for environmentally available Pb showed that the soil sample contained about 95700 mgPb/kg Experimental materials soil. One kilogram samples of the air-dried, sieved soil were weighed into 1 L polyethylene containers. The soil amend- The sample used for this experiment was collected from ments were applied to the soil in the plastic containers at rates slag guided by the results of preliminary studies of total envi- of 0 %, 5.0 % and 10.0 % phosphorus from the phosphorus ronmentally available metal determination. The phosphorus sources. The contents of the containers were mixed thor- sources used included soluble diammonium hydrogen phos- oughly and deionized water was added to obtain 20 % gra- phate (DAP): (NH4)2HPO4, less soluble calcium hydrogen vimetric moisture content. The soil samples were then mixed phosphate (CHP): CaHPO4 and the combination of the two again. The plastic containers were covered partially to reduce (DAP + CHP). Less soluble CHP and soluble DAP were cho- moisture loss and to allow for gas exchange. sen as the phosphate chemical amendments because H+ and The soil samples were incubated at room temperature for PO 3-4 ions are easily more released than the insoluble apatite 12 weeks. Sub-sampling of the incubated soils was done after and phosphate rock used in other studies (McGowen et al., one week and subsequently at 4 weeks intervals. The water 2001). content of 20 % per Kg soil was ensured by re-watering each 182 JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT VOLUME 35, NO. 3 AUGUST 2009 UNIVERSITY OF IBADAN LIBRARY container once weekly. The soils were thoroughly mixed at mm, were weighed into sealed wide-mouth 100 mL polyeth- weekly intervals. At the different incubation times sub sam- ylene jars. Fifty millilitres of 0.1M sodium acetate buffer was ples of approximately 100 g were taken from the containers added and the mixture was agitated on an end-to-end shaker after thorough mixing,. The sub-samples were air-dried, for 18 hours at 30 rpm. The extracts were stirred with a glass sieved to < 2 mm and analyzed for pH, Oslen-exractable P, rod after the required period had elapsed. The extracts were Pb fractions and TCLP-extractable Pb. transferred into polyethylene centrifuge tubes and separation was done by centrifuging at 5,000 rpm for 30 minutes. The Quality control: All treatments and analyses were carried out supernatants were acidified by 0.2 conc. HNO3 to pH < 2 in duplicate. For every batch of samples processed, a method until analysis when they were analyzed with AAS. blank was included and appropriate corrections made. Statistical analysis Determination of pH of the incubated soil Data were analyzed using one-way ANOVA of SPSS Soil pH was measured in a 1:1 ratio of soil to water (w/v) statistical package version 14.0. Significant means were sepa- using a glass electrode pH meter. rated using Duncan multiple range F-test. Ten grams of the air-dried soil samples was added to 10.0 mL of deionized water. The pH was measured after the mixture was stirred at 10 minutes interval for 30 minutes and RESULTS AND DISCUSSION then left standing for 1 hour. Determination of available phosphorus Soil properties in the amended soils The analytical parameters of the experimental soil are shown in Table 1. The estimated level of Pb that could be The available phosphorus in the amended soils was ex- available and cause injury in the environment was found to be tracted with Olsen’s reagent (0.5 M NaHCO3 adjusted to pH 95700 mg/kg soil. The pH of the experimental soil was 8.2, 1:20 soil/solution ratio) and determined colorimetrically mildly acidic. Phosphorus content of the soil indicated that by molybdenum blue ascorbic acid method (Stewart, 1989). the soil was deficient in phosphorus. This can be an added advantage to the choice of phosphate remediation of the con- Leaching of incubated soils taminated site. The high concentration of TCLP extractable Pb presents the site as hazardous and requires remediation. The effectiveness of the chemical treatments in immobi- lizing lead in the incubated soils was tested by comparing the Effect of phosphate amendments concentrations of lead in the chemically treated soils to those on Soil pH of the untreated soils. The sequential extraction procedure developed by Tessier et al (1979) was modified for the study. The pH of the incubated soils was monitored to verify The procedure was modified to separate heavy metals into the impact of the amendments on soil acidification. This was six operationally defined fractions: water extractable, ex- to ensure that during field application, some other toxic met- tractable with water ; exchangeable, extractable with 1.0 M als that might be present in the soil would not be made active MgCl2 at pH 7; specifically sorbed and carbonate bound, due to increased acidity of the amended soil, thereby creating extractable with 1.0 M (CH3COONa) adjusted to pH 5.0; an additional environmental risk. The pH of the experimental metals associated or sorbed or occluded mainly on iron or soils, including that of the control, varied slightly with time manganese oxides, extractable with hydroxylamine as shown in Figures 1 and 2. The reason for the variation was (NH2OHHCl in HNO3); strongly complexed by organic mat- unknown, although it might be due to the effect of microbial ter, extractable with H2O2 in HNO3; and residual extracted activities. The pH varied according to the type of phosphorus with 4 M HNO3. sources and the amount added to the experimental soils. The pH ranged from 5.17-5.26 (control), 4.88-5.58 (DAP), 5.01- Toxicity testing of the incubated soils 5.50 (CHP) and 4.83-5.52 (DAP+CHP). The highest change was observed at week 8. After one week of P application, all Samples of 2.5 g of air-dried incubated soil, sieved to < 2 TABLE 1 Analytical parameters of the experimental soil Pb (mg/kg) pH P (mg/kg) TCLP extractable Pb (mg/L) 95700 5.2 2.83 50.4 EFFECTS OF PHOSPHATE CHEMICALS TREATMENTS ON AUTO BATTERY WASTE CONTAMINATED SOIL IN NIGERIA 183 UNIVERSITY OF IBADAN LIBRARY 5.6 Control DAP 5.4 CHP DAP+CHP 5.2 5 4.8 4.6 4.4 1 4 Time (week) 8 12 Fig. 1. Effects of 5% Phosphorus with incubation time on soil pH 5.8 5.6 5.4 5.2 5 4.8 4.6 4.4 1 4 8 12 Time (week) Fig. 2. Effects of 10 % Phosphorus with incubation time on soil pH the amendments except 10 % CHP caused a slight decrease in Ca HPO + H O (l) dissolution4 2 Ca2+ (aq) + H2PO -4 (aq) + the pH of the treated soils from 5.19 (control) to a minimum of 4.83 (DAP + CHP). The application of DAP and OH- (aq)(Calcium hydrogen phosphate) DAP+CHP produced the highest decrease in the pH of the treated soils. It was apparent that the reduction in pH pro- duced by the mixture was influenced primarily by the pres- 5Pb2+ (aq) + 3H PO - (aq) + H O (l) pyromorphite formation 2 4 2 ence of DAP. Bolan and Duraisamy (2003) and Pierzynski [Pb5 (PO4)3OH] (s) + 7H+ (aq) and Schwam, (1993) documented similar observations with (pyromorphite) DAP. The initial reduction in pH observed with the phosphate treated soils may be explained by the following soil reactions These equations show that the initial reduction in pH pro- in the generation of protons during pyromorphite formation: duced by the phosphate treated soils resulted from the genera- tion of protons during pyromorphite formation. Ammonium (NH4)2 HPO4 (s) + H O (l) dissolution2 ions produced during DAP dissolution were nitrified to nitric acid (HNO3) by soil microbes. This is suspected to be the 2NH + 4 (aq) + H PO - -2 4 (aq) + OH (aq) reason why the reduction in pH was more pronounced with (Diammonium hydrogen phosphate) DAP. In contrast, such soil reaction was not observed to oc- cur with the CHP treated soil. This acidifying power of nitro- 2HNO + 6H+(aq) Nitrification by microbial action3 2NH + 4 (aq) + 3O (g) 2 gen fertilizers was reported to be partially neutralized during field application when plants took up the resulting NO -3 ions 184 JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT VOLUME 35, NO. 3 AUGUST 2009 UNIVER pHp HSITY OF IBADAN LIBRARY (Bolan and Duraisamy, 2003). contaminated soil may not require liming every time. Never- As the week of the incubation period increased, the pH theless, field applications of any of these chemicals on acidic of the amended soil adjusted naturally towards the pH of the soil as in the present study might require liming in order to control soil. It is worth noting that during the pyromorphite enhance the stability of the pyromorphite minerals formed. formation, hydroxyl ions were created thereby clarifying the pH adjustment towards the neutral side. At the end of incuba- Effect of time on extractable phosphorus tion period, all other amendments except CHP produced slight increments in the pH of the soil. For example, 5 %, 10 Removal of the available P from incubated soils over % DAP and 10 % mixture of DAP and CHP shifted the pH of time was recorded to estimate the effect of time on the pyro- the soil from 5.16 to 5.24, 5.58 and 5.52 respectively. The pH morphite formation in the treated soils. This was necessary to of the soils treated with 10 % CHP (5.16) at the end of the estimate the length of time the amendment would take to pro- incubation period was comparable to the pH of the untreated duce the desired results on the field applications. Reduction soil (5.17). Apart from the fact that the pH of the experimen- in the amount of phosphorus remaining in the soil with incu- tal soil itself was acidic as observed with the untreated soil, bation time was evident with all the amendments (Table 2), none of the amendments can be said to produce any undesir- implying that a reaction actually occurred in the soil between able effects on pH of the soil. The initial lowering of pH and lead and phosphorus. This removal was most likely a result of eventual increment induced by DAP-containing amendment lead phosphate mineral formation. Some authors have also may be an added advantage for a near neutral Pb- identified such phenomenon in both laboratory and field trials contaminated soil. The dissolution of soil Pb was compli- (Zhang and Ryan, 1999; Zhang et al., 1997; Cao, et al., 2002; mented by reduced pH, and stability of the Pb pyromorphite Chen et al., 2003). This however was contrary to the opinion formed was enhanced at near neutral pH (Chen et al., 2003; of other reports that the shaking during the sequential extrac- McGoween et al., 2001). The implication was that if the right tion to evaluate the effectiveness of the amendments might be proportion of any of the experimented amendments was used a major contributor to the formation of pyromorphite. on normal soil, it might not significantly alter the pH of the The results in Figure 3 show that immobilization of Pb as soil. Thus, the application of soluble phosphorus salts to lead- indicated by P removal was about 99.5 % completed by the TABLE 2 Effects of phosphate amendments on soil residual phosphorus % P in P source Chemical weight (g) P added (mg/kg) Sodium bicarbonate-extractable P (mg/kg) Week 1 Week 4 Week 8 Week 12 DAP 0.0 0.0 0.0 2.90 2.56 3.25 2.62 5.0 28.1 6600 34.7 26.9 25.9 25.3 10.0 56.3 13200 67.9 52.2 51.4 53.1 CHP 0.0 0.0 0.0 2.90 2.56 3.25 2.62 5.0 29.9 6800 33.6 26.8 24.9 22.4 10.0 59.7 13600.0 68.9 62.2 59.2 52.1 DAP + CHP 0.0 0.0 0.0 2.90 2.56 3.25 2.62 5.0 28.6 6650 38.8 28.3 28.0 25.5 10.0 58.0 12400 60.5 47.9 46.9 47.1 DAP = Diammonium hydrogen phosphate CHP = Calcium hydrogen phosphate EFFECTS OF PHOSPHATE CHEMICALS TREATMENTS ON AUTO BATTERY WASTE CONTAMINATED SOIL IN NIGERIA 185 UNIVERSITY OF IBADAN LIBRARY end of the first week of incubation. Hettiarachchi et al (2001) excessive growth of algae on surface water which may lead to also reported similar observations that the reaction between depletion of oxygen and blockage of sunlight available to soil Pb and P was likely to have occurred within the first aquatic life (Cao et al., 2002; Hettiarachchi et al., 2001; three days of incubation and the change was not significant McGowen et al., 2001). This necessitates the need to monitor thereafter. This indicated that there was rapid dissolution of the residual phosphorus in the phosphate remediated soils. soil lead aided by the reduced pH, presumably with a conse- Testing of soil P revealed that the concentration of phospho- quent reaction with the solution phosphorus to form pyro- rus in the untreated soil was about 2 mg/kg, showing that the morphite minerals. Larperche et al (1996) corroborate that the soil was deficient in phosphorus. Thus, there was an addi- conversion of lead (II) oxide (PbO) to pyromorphite was tional advantage in choosing phosphate remediation methods most rapid at pH 5.0. The almost complete reaction observed to decontaminate this site. within the first week of application suggested the appropriate The residual P in the treated soils ranged from 22.4-53.1 time frame is one week to lime an acidic lead-contaminated mg/kg, which accounted for less than 0.5 % of the P applied soil for optimum effective phosphate remediation technology. to the contaminated soil. This range is far less than the range The application of lime to phosphate treated soil earlier than a of total P concentrations of 200 to 5000 mg/kg soil normally week of application may increase the soil capacity for bind- encountered in soil as cited by Hiettiarachchi et al (2001), ing Pb, thereby limiting the release of Pb to react with the suggesting that the application of regulated amounts of any of solution P. Many reports investigating soluble phosphates as these phosphate chemicals to the contaminated site may cause sources of P for lead immobilization in contaminated soils little or no undue P increment in the environment. The con- applied lime at different times (Yang and Mosby, 2006; Het- centration of the residual P in the present study was in pro- tiarachchi et al., 2001; McGowen et al., 2001). This work, portion to the amount of P applied, corroborating the need to however, showed the first week of the treatment as the best be cautious in the amount of P introduced into the soil. time to apply lime. It was also speculated that the addition of The application of P as CHP yielded the least residual P lime after the phosphate treatment could augment the stabili- at the end of the incubation period while DAP produced the zation of excess added phosphate by the formation of calcium highest. This might have resulted from the formation of cal- phosphate or apatite which prevents the excess phosphate cium phosphate [Ca3(PO4)2] or apatite [Ca5(PO4 )3OH]; both from leaching out of the remediated soils (Yang and Mosby, are reported to be environmentally stable alongside with py- 2006). romorphite formation (Yang and Mosby 2006). Phosphorus sources and rates in relation Fractionation of Pb in an incubated soil to soil residual phosphorus The effectiveness of 5 % and 10 % P applications as There is need for caution when carrying out in-situ im- DAP, CHP and DAP + CHP in the incubated soils was evalu- mobilization of Pb in contaminated soil with the use of phos- ated using chemical fractionation procedure. The fractions of phate chemicals. Excess P in the environment may stimulate lead in the control soils were compared with the fractions of lead in the treated soils. The results are as presented in Figure 8000 7000 6000 5000 DAP CHP DAP+CHP 4000 3000 2000 1000 0 0 1 4 8 12 Time (week) Fig.3. Effects of incubation time on soil extractable phosphorus 186 JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT VOLUME 35, NO. 3 AUGUST 2009 UN P concentrIatVion (mg/kg)ERSITY OF IBADAN LIBRARY 4. Sequential extraction of the untreated soil showed that Pb was associated mainly with the residual fraction (85300 Water soluble Exchangeable mgPb/kg), followed by the Fe-Mn oxide (31900 mgPb/kg), 120000 Carbonate bound Fe-Mn Oxide carbonate bound (24300 mgPb/kg), organic matter bound D A P Organic matter Residual (12700 mgPb/kg), exchangeable (5680 mgPb/kg) and water 100000 soluble (266 mgPb/kg) fractions. Generally, the added phos- phate chemicals reduced the concentrations of Pb in water 80000 soluble, exchangeable, carbonate bound and Fe-Mn oxide fractions, and increased residual Pb concentrations in the treated soils when compared with the fractions of the un- 60000 treated soil. This is consistent with the results of Ma and Rao (1997) who reported that phosphate rock transformed Pb 40000 from non-residual forms to residual forms. Others document similar results that treatment of Pb-contaminated soil with 20000 phosphate chemicals results in the formation of pyromor- phites (lead phosphate) which has low water solubility (Berti 0 and Cunningham, 1997; McGowen et al., 2001; Ma et al., 0% 5% 10% 1995). The effects of reduction were primarily on water solu- % Phosphorus ble Pb followed by the Fe-Mn oxide bound fraction. Melamed et al (2003) and Chen et al (2003) observed a sig- nificant decrease in Fe-Mn oxide bound Pb upon applications 120000 of phosphorus. They attributed the decrease to the dissolution C H P of the oxides and release of sorbed Pb as a result of low pH initiated by the soluble phosphates. The reduction in the dis- 100000 tribution of Pb in the treated soil was less than expected, which might be due to the influence of the low pH of the ex- 80000 perimental soil. This reiterates the need for liming of acidic soil for effective phosphate chemical remediation. Five per- 60000 cent DAP, CHP and DAP + CHP produced 50.9, 61.6 and 79.1 % reduction in water soluble extractable Pb respectively 40000 while 10 % DAP, CHP and DAP + CHP produced 77.8, 84.2, 86.4 % reduction in water soluble Pb respectively. The main 20000 objective of the remediation technique is to eliminate or lower the most available form of contaminant in the polluted 0 soil, as noted in the present study. 0% 5% 10% Five percent DAP, CHP and DAP + CHP reduced the % Phosphorus sum of the water soluble, exchangeable, carbonate bound and Fe-Mn oxide bound fractions by 22.6%, 34.6% and 25% re- spectively while a 10 % P application as DAP, CHP and DAP + CHP caused 24.7%, 47.3% and 42.5 % reductions respec- 140000 DAP+CH P tively. The higher percentage of transformation of non- 120000 residual Pb to residual Pb resulting from a 10 % P application corroborated the theory that pyromorphite forms rapidly 100000 when sufficient Pb and P are present in aqueous solutions (Ma et al., 1993). When comparing the effectiveness of the P 80000 sources, CHP was more effective in transforming non- 60000 residual Pb to residual fraction. Ten percent CHP produced the highest reduction in Pb concentration in the fractions. It 40000 produced 84.2, 27.8, 55.5, and 44.2% reductions in water 20000 soluble, exchangeable, carbonate bound and Fe-Mn oxide Pb fractions respectively while DAP produced the least effec- 0 tiveness. Duncan one-way analysis of variance showed that 0% 5% 10% there were significant (p < 0.05) differences between the Pb % Phosphorus fractions in the treated soils and Pb fractions in the untreated Fig. 4. Effects of phosphate chemicals on the distribution soils. The analysis also confirmed 10 % P application to be of Pb in the incubated soils at 12 weeks the most effective and CHP to produce more effectiveness than others. All the amendments at the different rates caused a slight increase in the Pb concentrations in organic fraction, with 5 EFFECTS OF PHOSPHATE CHEMICALS TREATMENTS ON AUTO BATTERY WASTE CONTAMINATED SOIL IN NIGERIA 187 UNIVERSITY OF IB mgPb/kgsoil AmgPb/kgsoil mgPb/kgsoilDAN LIBRARY % P application causing the highest increase. This observa- CHP produced the overall effect of reducing bioavailable Pb tion may be connected with acidic nature of the incubated with little or no impact on soil acidification and least residual soils. The pH of the soils that received 5 % DAP, CHP and P. DAP + CHP at the end of the 12 weeks incubation period were 5.24, 5.05 and 5.13 respectively, and those of 10 % DAP, CHP and DAP + CHP were 5.58, 5.16 and 5.52 respec- CONCLUSION tively. These observations demonstrated that increases in pH would favor stability of the newly formed lead phosphate. The application of phosphorus sources in incubation This inference further emphasizes the need to lime acidic soil. studies did not result in soil acidification. Consequently, the re-mobilization of metals in field applications using this tech- Toxicity characteristics leaching procedure nology is almost ruled out. The application of phosphate chemicals at the experimented rates did not show excessive Toxicity characteristics leaching procedure (TCLP) of residual soil phosphorus; therefore, undue environmental untreated soils was 50.4 mg/L and was noticed to be well impact is not anticipated in the field application of the above the critical level of 5 Pb mg/L recommended by the method. The addition of phosphate chemicals to the contami- United States Environmental Protection Agency (Chen et al., nated soils reduced the concentrations of Pb in water soluble, 2003). The addition of phosphate chemicals at the different exchangeable, carbonate bound and Fe-Mn oxide fractions, as rates significantly reduced the TCLP extractable Pb. A 5 % P well as increased residual Pb concentrations when compared application of all the phosphate chemicals reduced the leach- with the fractions of the untreated soil. This demonstrates able lead from 50.4 mg/L to below 6 mg/l, and a 10 % P addi- effectiveness in reducing potential bioavailable lead. tion reduced it to below 5 mg/L, the regulatory limit of toxic- The addition of phosphate chemicals at the different rates ity characteristic leaching procedure (Table 3). The highest significantly reduced the TCLP extractable Pb below the reduction in TCLP extractable Pb concentration (2.75 mg/L) USEPA regulatory levels of 5.0mg/L, predicting potential was caused by 10 % CHP, indicating that a 10 % P applica- reduction in the hazardous status of the site during field ap- tion as CHP is more effective at reducing the hazardous status plication. of the soil than other applications. This was consistent with Considering the reduction of bioavailable Pb in the the results for fractionation of Pb in the incubated soils where treated soil , the low contents of the residual phosphorus , and TABLE 3 Mean concentrations of TCPL extractable Pb in incubated soils Mean Pb % P in P source (mg/L) DAP 0.0 50.4 5.0 5.09 10.0 2.85 CHP 0.0 50.4 5.0 5.38 10.0 2.75 DAP + CHP 0.0 50.4 5.0 5.93 10.0 4.24 188 JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT VOLUME 35, NO. 3 AUGUST 2009 UNIVERSITY OF IBADAN LIBRARY the excellent reduction in TCLP leachable Pb with little or no 11. Chen, M., L.Q.S.P. MaSingh, R.X. Cao, R. Melamed, impact on soil acidification, 10 % phosphorus amendments as 2003. “Field demonstration of in situ immobilization of DAP, CHP and DAP+CHP, especially CHP, can be promis- soil Pb using P amendments.” Advances in Environ- ing remediation techniques for the studied site. Upon deter- mental Research, Volume 8, pp. 93–102. mining the total Pb concentrations in a particular Pb contami- 12. Chopin, E.I.B., S. Black, M.E. Hodson, M.L. Coleman, nated soil, the amount of the phosphate amendment required B.J. Alloway, 2003. “Preliminary investigation into min- can be extrapolated based on the results of this study. ing and smelting impacts on trace element concentrations in the soil and vegetation around Tharsis, SW Spain.” Mineralogical Magazine, Volume 67, No. 2, pp. 279- REFERENCES 288. 13. Everhart, J.L., M.J. David, E. Peltier, D. Van der Lelie, 1. Agency for Toxic Substances and Disease Registry, R.L. Chaney, D.L. Sparks, 2006. “Assessing nickel 1988. The nature and extent of lead poisoning in children bioavailability in smelter-contaminated soils.” Science of in the United States: A report to Congress. U.S. Public the Total Environment, Volume 367, Nos. 2-3, pp. 732- Health Service, Washington, DC. 744. 2. Agency for Toxic Substances and Disease Registry, 14. Hettiarachchi, G.M., G.M. Pierznski, 2000. The use of 2005. Toxicological Profile for Lead. U. S Department of phosphorus and other soil amendments for in-situ stabili- Health and Human Services. Public Health Service, zation of soil lead. Proceedings of the 2000 conference Agency for Toxic Substances and Disease Registry Divi- on Hazardous Waste Research: Environmental chal- sion of Toxicology and Environmental Medicine/Applied lenges and Solutions to Research Development, Produc- Toxicology Branch 600 Clifton Road NE, Mailstop F 32, tion and Use, Great Plains/Rocky Mountain Hazardous Atlanta, Georgia 30333. Substance Research Center, Denver, CO, May 20-23, 3. Andy, R., D. Roberts, 2002. “Health effects and land- 2000. 125-133. fills.” Issues in Environmental Science and Technology, 15. Hettiarachchi, G.M., G.M. Pierznski, M.D. Ransom, Volume 8, pp. 103-139. 2001. “In situ stabilization of soil lead using phospho- 4. Balkrishena, K., S.S. Randhir, D. Conrado, R. Franklin, rus.” Journal of Environmental Quality, Volume 30, pp. 1999. “Follow-Up Screening of Lead-Poisoned Children 1214–1221. near an Auto Battery Recycling Plant, Haina, Dominican 16. Kaul, B., R.S. Sandhu, C. Depratt, F. Reyes, 1999. “Fol- Republic.” Environmental Health Perspectives, Volume low-up screening of lead-poisoned children near an auto 107, pp. 917-920. battery recycling plant, Haina, Dominican republic.” En- 5. Berti, W.R., S.D. Cunningham, 1997. “In-place inactiva- vironmental Health Perspectives, pp. 107: 917-920. tion of Pb in Pb contaminated soils.” Environmental Sci- 17. Laperche, V., T.J. Logan, P. Gaddam, S.J. Traina, 1996. ence and Technology, Volume 31, pp. 1359-1364. “Chemical and mineralogical characterizations of Pb in a 6. Bolan, N.S., V.P. Duraisamy, 2003. “Role of inorganic contaminated soil: reactions with synthetic apatite.” En- and organic soil amendments on immobilization and vironmental Science and Technology, Volume 30, pp. phytoavailability of heavy metals: a review involving 3321-3326. specific case studies.” Australian Journal of Soil Science, 18. Li, J., Z.M. Xie, Y.G. Zhu, R. Naidu, 2005. “Risk as- Volume 41, pp. 533-555. sessment of heavy metal contaminated soil in the vicinity 7. Boularbah, A., C. Schwartz, G. Bitton, W. Aboudrar, A. of a lead/zinc mine.” Journal of Environmental Science, Ouhammou, J.L. Morel, 2006. “Heavy metal contamina- Volume 17, No. 6, pp. 881-885. tion from mining sites in South Morocco: 2. Assessment 19. Ma, Q.Y, S.J. Traina, T.J. Logan, 1995. “Lead immobili- of metal accumulation and toxicity in plants.” Chemos- zation from Aqueous Solutions and Contaminated Soils phere, Volume 63, pp. 811–817. Using Phosphate Rocks.” Environmental Science and 8. Brown, S., R.L. Chaney, J.G. Hallfrisch, J.A. Ryan, Technology, Volume 29, pp. 1118-1126. W.R. Berti, 2004. “In Situ Soil Treatments to Reduce the 20. Ma, Q.Y, S.J. Traina, T.J. Logan, J.A. Ryan, 1993. “In Phyto- and Bioavailability of Lead, Zinc, and Cad- situ lead immobilization by apatite.” Environmental Sci- mium.” Journal of Environmental Quality, Volume 33, ence and Technology, Volume 27, pp. 1803–1810. pp. 522-531. 21. Ma, Q.Y., G.N. Rao, 1997. “Effects of phosphate rock on 9. Cao, X., L.Q. Ma, M. Chen, S.P. Singh, W.G. Harris, sequential chemical extraction of lead in contaminated 2002. “Impacts of phosphate amendments on lead bio- soils.” Journal of Environmental Quality, Volume 26, geochemistry at a contaminated site.” Environmental pp. 788–794. Science and Technology, Volume 36, No. 24, pp. 5296- 22. Ma, Q.Y., S.J. Traina, 1999. “Aqueous Pb reduction in 5304. Pb-contaminated soils by Florida phosphate rocks.” Wa- 10. Centers for Disease Control, 1991. Preventing lead poi- ter, Air, and Soil Pollution, Volume 110, pp. 1–16. soning in young children. Atlanta, GA, U. S. Department 23. McGowen, S.L., N.T. Basta, G.O. Brown, 2001. “Use of of Health and Human services, public Health service, diammonium phosphate to reduce heavy metal solubility Centers for Disease Control and Prevention. Accessed and transport in smelter-contaminated soil.” Journal of from http://wonder.cdc.go/wonder/prevguid/p0000029 Environmental Quality, Volume 30, pp. 493-500. /0000029.asp May 18, 2007. 24. Ownby, D.R., K.A. Galvin, M.J. Lydy, 2005. “Lead and EFFECTS OF PHOSPHATE CHEMICALS TREATMENTS ON AUTO BATTERY WASTE CONTAMINATED SOIL IN NIGERIA 189 UNIVERSITY OF IBADAN LIBRARY zinc bioavailability to Eisenia fetida after phosphorus dure. amendment to repository soils.” Environmental Pollu- 31. Yang, J., Mosby, D.E., 2006. “Field assessment of treat- tion, Volume 136, pp. 315-321. ment efficacy by three methods of phosphoric acid appli- 25. Peplow, D., R. Edmonds, 2005. “The effects of mine cation in lead-contaminated urban soil.” Science of the waste contamination at multiple levels of biological or- Total Environment, Volume 366, pp. 136-142. ganization.” Ecological Engineering, Volume 24, Nos. 32. Yang, J., Mosby, D.E., Casteel, S.W., Blanchar, R.W., 1-2, pp. 101-19. 2001. “Lead immobilization using phosphoric acid in a 26. Pierzynski, G.M., A.P. Schwab, 1993. “Bioavailability of smelter contaminated urban soil.” Environmental Science zinc, cadmium and lead in a metal-contaminated alluvial and Technology, Volume 35, pp. 3553–3559. soil.” Journal of Environmental Quality, Volume 22, pp. 33. Zhang, P. Ryan, J.A., Bryndzia, L.T., 1997. “Pyromor- 247-254. phite formation from goethite adsorbed lead.” Environ- 27. Sanghoon, L., 2006. “Geochemistry and partitioning of mental Science and Technology, Volume 31, No. 9, pp. trace metals in paddy soils affected by metal mine tail- 2673-2678. ings in Korea.” Geoderma, Volume 135, pp. 26-37 34. Zhang, P., Ryan, J.A., 1998. “Formation of pyromorphite 28. Stewart, E.A. 1989. Chemical analysis of ecological ma- in anglesite-hydroxyapatite suspensions under varying terials. 2nd Ed. Great Britain: Buller and Tanner. pH conditions.” Environmental Science and Technology, 29. Tessier, A., Campbell, P.G.C., Benon, M., 1979. “Se- Volume 32, No. 21, pp. 3318-3324. quential extraction procedure for the speciation of par- 35. Zhang, P., Ryan, J.A., 1999. “Formation of chloropyro- ticulate trace metals.” Analytical Chemistry, Volume 51, morphite from galena (PbS) in the presence of hy- pp. 844–851. droxyapatite.” Environmental Science and Technology, 30. US Environmental Protection Agency Method 1311. Volume 33, No. 4, pp. 618-624. SW-846, 1992. Toxicity Characteristic Leaching Proce- 190 JOURNAL OF SOLID WASTE TECHNOLOGY AND MANAGEMENT VOLUME 35, NO. 3 AUGUST 2009 UNIVERSITY OF IBADAN LIBRARY